Apparatus for liquefying and separating gases.



R. MEWES. APPARATUS FCR LIQUEFYING AND SEPARATING GASES.

APPLICATION Patented Feb. 13,1917.

4 SHEE S-SHEET I.

R. MEWES.

APPARATUS FOR LIQUEFYING AND SEPARATING GASES.

APPLICATION FILED OCT. 7. 1915.

Patented Feb. 13, 1917.

4 SHEETS-SHEET 2.

mlwm

R MEWES. APPARATUS FOR LIQUEFYING AND SEPARATING GASES.

APPLICATION FILED OCT. 7'. I915. 1315,95? Patented Feb. 13,1917.

4 SHEETS-SHEET 3- ATTORNEYS R. MEWES. APPARATUS FOR LIQUEFYING ANDSEPARATING GASES.

APPLICATION FILED 0C1], l9l5- Lglfifi j. Patented Feb. 13,1917.

4 SHEETS-$HEET 4- nUnoLF mnwns, or

BER-LIN, GERMANY.

APPARATUS FOR LIQUEFYING AND SEPABATING GASES.

1,215,957. Specification of IettersP-atent- Patented Feb. 13, new.

Application filed October 7, 1915. Serial No. 54,601.

To all whom it may concern:

Be it known that I, RUnoLr Mnwns, a subject of the King of Prussia,residing at Berlin, in the Kingdom of Prussia and German Empire, haveinvented new and useful Improvements in Apparatus for Liquefying andSeparatin Gases, of which the following is a speci cation. I

My present invention relates to an im? provement of the process forliquefying air and other gases described and claimed in my Patent No.1,188,191 dated June 20, -1916.

In the cited application the cold gas mlxture (for example oxygen andnitrogen) is alternately raised and lowered in temperature, and thusseparated into its constituents the gas compressed to a higher pressureis by contact with coils containing relatively warmer and colder gases.

Now according. to the present invention the. raising of the temperatureof the gas mixture in the separating chamber is also effected by gas ata higher pressure introduced in a coil and then expanded into thechamber and thus producing a very low tem-:

Q perature'.

In the drawing several constructions of apparatus for carrying out theimprovement are shown by way .of example.

- Figure 1 is a sectional outline of one con-f structionvin which theseparating chamber is arranged in vertical -position and is surroundedby a counter current apparatus Fig. 2 is asimilar section of anapparatus working on exactly the same principle as preliminarily cooleddirect by the exhaust- .of the expansion engine and, then enters a coilpassing through the separating chamber. Other differences of thisconstruction compared with that shown in Fig.1 will be clear from thedescription given below;

Fig. 7 is a sectional outline of another con-- struction of theseparating chamber in annular form.

passage a after leavin by contact with the coi It in the chamber d.

Fig. 5 is a section on the line C-D in Fig.

The apparatus shown in Fig. 1 comprises a counter current coolingapparatus a. which surrounds a gas separating chamber d. The countercurrent chamber is divided by' a spiral partition a." into a spiralpassage a? containing a coil 1); Into'this coil low pressurejairof 5-10atm. is introduced at n which passes through the .whole length ofthe-coil and then'enters a heating coil 5 which is arranged in themiddle of the separating chamber 03 and terminates at Z, so-

that the low Pressurair, passing through the coil 11 escapes into thechamber 01. From the chamber d the -air passes through the pipe to theexpansion cylinder 0, from whence it passes through the pipe It andchamber y to the cooling coil 71. which, like the coil z,is arranged inthe middle off-the chamber (2, its, separate windings being between thewindings of the coil 73. The lower end .of the pipe-h opens intothespiral pas-- sage. a so that the cold expanded air, after leaving thecoil it, will pass throughthe passage a? in counter current to the airpassing through the pipe I) and it leaves said spiral passage "at 0, inorder to pass to a vacuum pump, into the atmosphere, or to the suctionside of the low pressure compressor which supplies air .to the coil 7)at n,'none of which are shown in the drawing because they do not formpart of the invention.

n will be clear that in the chamber a the air issuing from the pipe 5will be partially liquefied,1 owing to its having been cooled, firstlyin the coil 6- which is in-"contact with the cold expanded air passingthrough the the coil k, secondly As a consequence, oxygen will have thetendency to collect at the bottom, and nitrogen will rise more to the'top of the chamber 0!.

Now from the bottom end of the-chamber 0? air rich in oxygen is drawn011 through the pipe 12 to a high pressure compressor P- with coolingmantle to carry ofi the heat of compression. In this compressor the airis raised to a higher pressure for example 40-60 atm'. Thus highlycompressed air at a temperature of 6( C. or more, returns through thepipe g and :p asses into the .heat:

ing coil 1', which is shown inside the'coilc". The coil 1* extendsthrougl'nthe entire length of the coil 2' and terminates in thethrottling valve Z, through which the highly compressed air escapes intothe chamber It will be clear that, owing to the high pressure of the airin the pipe 1', it will be liquefied in this pipe, and-on issuing fromthe valve Z, it will have the tendency to expand and thus assist inlowering the temperature in the chamber d.

In the same way air rich in nitrogen is drawn ofi? from the pipe mthrough the pipe '7) and passes to a high pressure compressor Q by whichthe pressure is raised to a high pressure, for example 40-60 atm. Thehighly compressed air returns at a temperature of C. or more through thepipe 1 and enters the coil r which is arranged to inclose the coils zand 1' for a portion of their length. The coil 1- ends in thethrottling, valveZ. Through this valve the liquid nitrogen escapes intothe chamber (1, and, in escaping, expands, thus materially assisting inreducing the temperature. It will be understood that the throttlingvalves Z and Z" at the ends of the coils r and 1' reduce the pressure ofthe air passing out of said coils.

Further, a pipe at leads from the lower part of the chamber d, whereoxygen, or air rich in oxygen, enters it, and thisgas rises into thecoil 3 provided in the chamber y. As, this chamber y is cooled by theexpanded air coming from the cylinder 0 the gas in the coil will beliquefied and will be led by the other limb of the coil to the middle ofthe chamber d, where the pipe is bent around to form a liquid seal. Inthe same Way a' pipe 1) leads from m to the coil '0 also provided in thechamber y, and the nitrogen, or air rich in nitrogen, which enters thepipe 11, will be condensed in the coil *1)? and will be led by the pipe'2) to the chamber d,where it will evaporate and produce cold. As shownin the drawing the pipe V is bent at itsend to form a liquid seal,,sothat only liquid, and not' gas can escape into the upper part of thechamber cl, and by its evaporation lower the temperature. Circulationtakes place in the coil V because the temperature producedrbytheevaporation of the liquid at the upper part of chamber 01 is not aslowas that in the chamber 3 As mentioned above, by the coil h the air orgas in the chamber cl will .be cooled, while the pipes z, r, 1* willexercise a heating effect. By this alternate heating and cooling an"alternate condensation and evaporation will be obtained, which resultsin a good separation of the constituent gases.

The liquid oxygen is collected in the receiver e and can be drawn offthrough thecock f.

It is to be understood that the chamber (Z is a rectification chamber,and it is impossible for gaseous oxygen to reach the top end of thechamber, because the temperature at the top is too low, owing to thecooling influence of the expanded air in the pipe 12.. The

air liquefied in chamber (1 comes into contact'with the pipes 71. and rand is accordingly alternately heated and cooled. It is clear that thisheating and cooling will have arectifying influence. It will also beclear that, because no gaseous oxygen can reach the top of the chamber(l'owing to the low temperature at that part of (I, only nitrogen willpass into the expansion cylinder 0, and that the nitrogen on returningthrough the pipe it will exercise a very strongcooling action.

Figs. 2 and 3 show a horizontal apparatus working on the same principleas the vertical apparatus shown in Fig. 1. I

a isthe counter current. apparatus in which is provided the coil b, intowhich compressed air of about 5 to 10 atmospheres is fed at n. Afterpassing through the entire length of the coil 11' the air passes intotwo coils z" of S-shape passing through the separating chamber d andending in a pipe Z which opens out into the middle of the chamber (1.The chamber d is divided into a number of compartments by verticalpartitions (P, which however leave a space at the bottom-and toprespectively which will enable the air to pass from one end of theapparatus to the other. From the chamber d the air passes to theexpansion engine 0 through the pipe 721/, returning through the pipe 71.which is divided into three cooling coils k arranged at right angles tothe coils i, ending in the pipe is, which opens into the counter currentapparatus a. After passing through the chamber of the apparatus a theair escapes through 0 tothe atmosphere, or to a suction pump, or tothesuction side of the compressor supplying compressed air to the pipeI) at n.; The separating chamber d can have a small incline from theexpansion cylinder end downward to the opposite end. In any case however liquid oxygen will-collect at the right .end, and liquid nitrogenat the left end of the chamber d Oxygen or. air rich in oxy-.

gen is drawn off through thepipe p and compressed to a pressure of about40-60 atm.,

whereupon it returns through the pipeiq and enters the heating'coil 1",which is arranged parallel to the coil z" and ends in the valve Z, sothat the highly compressed liquid oxygen expands into the chamber d.From the opposite end of the chamber .03 nitrogen is drawn oflthrough-the pipe 79 and, after being compressed to about 50-60 atm., isreturned through the pipe and enters the coil 1", which is also arrangedparallel to the coil 2', and ends in the valve 1 through which thehighly compressed liquid nitrogen expands into the chamber (1.

The liquid oxygen is drawn ofi' through the cock f.

.In Figs. 4 and 5 another horizontal construction. of the separatingchamber is ramps? shown, the relative position of the countercurrent-cooling apparatus being represented in dotted lines.

According to this construction the separating chamber 01 is composed ofa number of parallel elements d by the partitions d. The lower part orliquid chamber of each element is connected to the same chamber of thenext element by a pipe at. In each element there is a partition d havingan opening d in the middle, through which the liquid formed in the upperpart of the element flows irto the lower parts Z, l. The partition 03prevents the gases evaporating in Z and Z" from mixing with the gases inthe chamber d Above the level of the liquid in the chambers Z, Z a pipe(I is attached which leads to the top part of. the next element.Transve'rsely through all the elements a? pass the pipes 72;.

In operation the low pressure air of 510 atm., after passing through thecounter current apparatus a, enters one of the elements d at 1 near themiddle of the whole series. The air passes out of the end element dthrough the pipe m to the expansion cylinder not shown in Figs. 4 and 5,because the arrangement will be clear from Figs. 1 and 2. The expandedair returns through the pipe 11. and then passes through the pipes 711*.from one end of the apparatus to the other and is then conducted by thepipe to the counter current apparatus a.

From the right end of the apparatus oxygen or air rich in oxygen isdrawn ofi through the pipe ;0* to a compressor by which it is raised toa pressure of about 40-60 atm. and returned through the pipe 9,- Whichleads to the coil 1 in the compartment Z". After leaving the coil r theair enters one of the middle elements (Z through a cock I.

From the left end of the apparatus nitrogen or air containing but littleoxygen is drawn off through the pipe 39 to a compressor, by which it israised to about l() to 60 atm. and then returned through the pipe 9 fromwhich it enters the coil 7 On middle chambers at through a cock Z Theapparatus represented in Fig. 6 operates on the same principle as thatshown in Fig. 1, but the construction is somewhat different.

The counter current cooling apparatus a,

with its coils b surrounds the separating chamber d, but the lowpressure air is not fed into the coil 6 as in Fig. 1, but into thespiral passage formed by the windings of said coils touching each other.Said low pressure air enters at 11*, a that is, at two different points,in order to well distribute it. After passing through the spiral passageformed by the windings of the coils and thus being cooled, it passesthrough the opening Z into the separating chamber (2.

passes, in order to escape at 0 In this construction the expanded airfrom the cylinder 0 does not exercise any cooling efiect in theseparating chamber d because it is led direct into the counter-currentcooling device. From the pipe m a pipe 7) is branched ofi which iswoundinto the form of a coil 20 surrounding the expansion engine and itsconnection with the compressor. After leaving the cooling pipe 1) theair passes into the upper end of the com- By the upward motion of thepressor p piston this air is forced to the lower end of the compressorcylinder and by the return motion of the piston it is compressed to 40to 60 atm. and leaves the compressor through the coil 9 from whence itpasses through the coil 9 which leads into the coil 1". This coil lee dsto the top of the chamber 03 and then returns through the coil 1*", inorder to escape out of the pipe 1* into the chamber h; from whence itpasses through the coil 6 to 0 The oxygen collecting in the bottom partof the chamber (l passes through the pipe 10* to the coil 1* Which issubjected to the intense cold given ofi by the coils 1", T The liquidoxygen formed will issue through the pipe 1".

The expansion cylinder is shown with a single insulating jacket I andthe compressor with a double insulating jacket I, I.

The separating chamber shown'in Fig. 7 has an annular form and isdivided by the spiral plate '0 into one continuous annular passage. Inthe passage so formed the spiral pipes 72 and 'r" are provided. The lowpressure air of 5 to 10 atm. is introduced into the spiral passage at Zand passes off at m to an expansion engine, for example of thekind-shown in Fig. 1. After being expanded the air is fed to the coil 78at h and passes through the whole length of this coil, in order to passoff at 7: into the counter current device. At the bottom end of thespiral chamber (i the oxygen or air rich in oxygen is drawn off throughthe pipe p and compressed to a high pressure, whereupon it is returnedthrough the pipe 9 and enters the coil 0". After passing through thewhole length of the coil 1-, the high pressure air is led to the middleof the chamber (i through the pipe Z' in which a throttling valve isprovided. as shown in the drawing. The oxygen liquefied in the chambera? flows over plates 0., to the bottom of the spiral passage formed bythe spiral plate '0 and in flowing along the spiral plate a it cools thehigh pressure air in the pipe 7. The liquid oxygen is drawn off throughthe pipe 6 In all the above examples exclusively air has been mentioned,but it is clear that not only air, but also other gases can be treatedin the same way, and the claims are meant to include apparatus forliquefying and separatingsocalled permanent gases of all kinds.

What I claim and desire to secure by Letters Patent of the United Statesis 2-- 1. The described apparatus for liquefying and separating thecomponents of air, which comprises in combination, a counter currentdevice for cooling air of low pressure, a separating chamber, a coilinside said chamber to which the low pressure cooled air is fed, saidcoil opening into said chamber, a pipe connecting said chamber with theexpansion cylinder, a second coil in said chamber, a

pipe connecting said second coil with the exhaust of said expansioncylinder, a suction pipe for air rich in oxygen, a high pressure cooledcompressor connected with said suction pipe, a third coil in saidseparating chamber, a force pipe connecting said high pressurecompressor with said third coil, and a throttlingvalve at the end ofsaid thirdcoil, substantially as, and for the purpose, set forth.

2. The described apparatus for liquefying and separating the componentsof air, Whichcomprises in combination, acounter current device forcooling air of low pressure, a separating chamber, a coil inside saidchamber to which the low pressure cooled air is fed, said coil openinginto said chamber, a pipe connecting said chamber with the expansioncylinder, a econd coil in said chamber, a pipe connecting said second'coil with the exhaust of said expansion cylinder, a

- suction pipe for air rich in oxygen, a high pressure cooled compressorconnected with said suction pipe, a third coil in said separatingchamber, a force pipe connecting said high pressure compressor with saidthird coil. a throttling valve at the end of said third coil. a suctionpipe for air containing little oxygen, a second high pressure cooledcompressor connected with said suction pipe,

a fourth coil in said separating chamber, a

force pipe connecting said second high pressure compressor with saidfourth coil, and athrottling valve at the end of said fourth coil.substantially as, and for the purpose, set forth.

2-3. The combination with a chamber in which air is liquefied by beingled under low pressure through said chamber in counvter current toexpanded cold air, of a pipe containing high pressure air arranged incounter current to said expanded air and opening out into said chamber,substantially as, and for the purpose, set forth.

'4. The combination 'with a chamber in which air is liquefied by beingled under low pressure through said chamber in counter current toexpanded cold air, of a pipe containing high pressure air rich in oxygenarranged in counter current to said expanded air and opening out intosaid chamber, substantially as, and for the purpose, set forth,

ber and a )i )e containin air com arativelv rich in nitrogen arranged incounter current to said expanded air and opening out into said chamber,substantially as, and for the purpose, set forth.

6. The combination with an expansion cylinder of a chamber, a coil insaid chamber, a pipe connecting said coil with the exhaust of saidcylinder, a second coil in said chamber and arranged adjacent to saidfirst coil and containing low pressure air, a third coil in said chamberand adjacent to said first and second coils and containing high pressuregas, a fourth coil in said chamber also containing high pressure gassaid second, third, and fourth coils all opening out intosaid chamber,and a pipe connecting said chamber with said expansion engine,substantially as, and for the purpose, set Iorth.

7. The described apparatus 'for liquefying air and separating itscomponents, comprising in combination, a chamber to which low pressurecooled air is fed, a coil in said chamber, a high pressure cooledcompressor, a pipe connecting the top end of said chamber with the inletport of said compressor, a second pipe connecting said coil with theoutlet side of said compressor, a further coil arranged in said chamber,and a pipe leading from near the bottom of said chamber andcommunicating with said last mentioned coil, substantially as set forth.

In testimony whereof I have signed my name to thi specification in thepresence of two subscribing witnesses.

, RUDOLF MEWES.

Witnesses:

\VoLnnMAn HAUP'r, HENRY Hasrnn.

